Arrangement for feeding vacuum tubes



Jan. 18 1927. 1,615,098

E.PORSCHEL ARRANGEIENT FOR FEEDING VACUUI TUBBS Filed Sept. 30, 1922 awbmlio'c a Patented is, 1921. 1 UNITED STATES PATENT OFFICE.

ERNST rtmscnun, or BERLIN, GERMANY, nssionon T more CORPORATION or AMERICA, 4 conromrionor DELAWARE.

I ARRANGEMENT FOR FEEDING VACUUM TUBES.

Application filed September 30, 1922, Serial No. 591,480, and in Germany September 22, 1921.

The invention relates to an arrangement for feeding vacuum tubes used as receivers or amplifiers, and makes possible the connection of such apparatus to any available 5 line carrying alternating current or to machines producing such currents, thereby ren dering the provision of special batteries for filament heating and anode potential no longer necessary.

The accompanying drawing shows one exempliiication of the present invention.

In the drawing, N indicates the end of an alternating current line. From this line the current passes in parallel through transformers Tr and Tr However, the two transformers may also be united.

The. coils K and L respectively of the transformer Tr supply the heating current for the heating current rectifier (ll and the anode potential rectifier G1 Furthermore, the coil M ofsnch transformer supplies the alternating current to be rectified to the heating current rectifier Gi For the purpose of example, the drawing illustrates a duplex Wehnelt tube Grl acting as a heating current rectifier and the anodes of the tube are connected to the opposite ends of the coil M so that current pulse is passed through therectifier during each half of the alternating current waves. Due to this a pulsating direct current is produced beyond the rectifier G1,, and the number of pulsations in this current correspond to double the frequency of the alternating current in the line N. V

The anode potential rectifier G'rl is, for the purpose of example, illustrated as a high vacuum, hot cathode tube which ermits the passage of only one current pu so during each alternating currentwave whereby pulsating direct current is obtained beyond rectifier G1,, having pulsations corresponding in number to the frequency of the g ourrent ob- Y tained from the line N.

The heat' direct current supplied by Grl is transmitted through a filter arrangement chain and series resistances to the cathodes of the receivingv and amplifying tubes. It is very important that one pole of the direct current heating line be ounded. In drawing the minus poe E is grounded.

The filter ent consists of two choke coils D and D, and two condensers (3 and C, The choke coils D and D,,-must four cathode tubes.

tubes are connected in series and with the always be provided in the ungrounded conductor of the direct current heating supply. The condensers are inparallel with the heating current source in front of and between the choke coils. In certain receiving systems the condenser C, may be left out. The drawing shows also two series resistances of which W is arranged for hand adjustment to be set only once, and W is arranged for automatically equalizing variationsiin the can rent supply lines.

The drawing represents a set comprising The cathodes of the negative and positive terminals E and H re spectively. R, isan audion tube provided their heating current supply circuit in front of the cathodes series resistances P from which the biasing grid potential is obtained.

A coil :D is preferably inserted in the positive lead of the anode circuit from the transformer Tr and a condenser U is ar ranged in. said circuit in parallel with the tubes R R R and R The present invention makes possible also the feeding of other tube combinations for high, medium or low frequency amplification. The series heating arrangement described for the purpose of exam le, aflords the smallest volume 'for the cho e coils D and D and for the heating current regulators W and W The above described arrangement makes possible the feeding from an alternating current line of a set of cathode tubes comprisinga plurality ofstages for very lar e receiving amplification whereby the Si e tones are weakened to-such an extent that the slightest signals or weakest speech will be left practicall undisturbed. Furthermore, the speech distortion is eliminated by meanswf the present arrangement and it was just this speech distortion which made heretofore impossible the use of alternating current or ulsating direct current for the heatingof e filament. v Having described my ingentlon, what I claimiis: f

Ina radio set, vacuum tubes having cathodes, grids and anodes means for supplying current to the catho es from source of alternating current includ' a transformer double wave thermionic rectifier associated with two of said windings and filtering circuits for the rectifier, a single wave thermionic rectifier, said cathodes being connected in series with resistances between them for producing a biasing potential betweenthe grids and cathodes of the tubes, means for supplying the'anodes with current, including a second transformer with a single sec- 10 ondary winding, said winding being associated with the output of the single wave thermionic rectifier, filtering circuits being sociated with the single wave rectifier, said filtering circuits having a common connection, the separate connections for each circuit including inductances, whereby a difference of potential between the vacuum tubes and the rectifiers produced by radio frequency currents is prevented.

ERNST PURSCHEL. 

